Presidential meetings usually are about classified information, which means that they can be top secret, secret and confidential. Usually, in these presidential meetings matters of national security and defense against terrorism are discussed and if information of these meetings is released to the public national security might be at risk.
Despite this, The Presidential Records Act - created in 1981 - determines the preservation of all presidential records. The Act determines that public access to Presidential records can begin five years after the end of the Administration.